Benefit Plans - Accumulated Other Comprehensive Loss That Have Not Yet Been Recognized as Components of Net Periodic Benefit Cost (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 28, 2014
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost, beginning balance	$ (97,580)
Actuarial Gain (Loss), Net periodic benefit cost	(54,239)
Reclassification Adjustments, Net periodic benefit cost	2,559
Net periodic benefit cost, ending balance	(149,260)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss, beginning balance	(71,787)
Actuarial gain (loss)	(53,597)
Reclassification Adjustments, Actuarial loss	1,743
Actuarial loss, ending balance	(123,641)
Prior service cost (credit), beginning balance	(199)
Actuarial Gain (Loss), Prior service cost (credit)	0
Reclassification Adjustments, Prior service cost (credit)	36
Prior service cost (credit), ending balance	(163)
Postretirement Medical [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss, beginning balance	(31,268)
Actuarial gain (loss)	(9,324)
Reclassification Adjustments, Actuarial loss	2,293
Actuarial loss, ending balance	(38,299)
Prior service cost (credit), beginning balance	5,674
Actuarial Gain (Loss), Prior service cost (credit)	8,682
Reclassification Adjustments, Prior service cost (credit)	(1,513)
Prior service cost (credit), ending balance	$ 12,843